aging defined
aging is a series of cumulative, progressive, intrinsic, and deleterious functional and structural changes that usually become measurable at or around the end of development, and that decrease the ability of the organism to respond to stressors and increa
a complex system is a system that is made up of many interacting parts and for which
the nonlinear, feedback-driven interactions cause the behavior of the whole system to be greater than the sum of its parts
which of the following are objects of the discipline of gerontology?
characterization of the mechanisms that regulate aging
why is human lifespan/longevity past 100 years of age considered to be "extreme"/"exceptional?
1. bc survival for men & women past age 100 is statistically rare
2. bc such a small fraction of humans live that long
list the causes of population aging
decreased fertility & death rate
increased life expectancy
survival curves are figures/plots/graphs of data that are taken from a
life table
the primary variables that may be determined from a survival curve include
healthspan
the rate of aging for a population can be estimated from the data in a life table by
determining the slope of the linear regression line that has been fit to the log-transformed age-specific mortality data
explain how health span may be determined from a survival curve
health span is the time period between the age at the end of development and the age at which 10% of the population has died (or age at which 90% of the population is still alive)
data from a survival chart, in particular the age-adjusted mortality, can be analyzed to determine if one population is aging more slowly or rapidly than another population. what is the basic premise that allows this analysis to reflect the "rate of aging
in a population, the rate of age-specific mortality can be considered to be a proxy for aging
biological age defined
an estimate of the functional status of an individual compared to her/his peers
biological age is...
- a function of within and between individual differences in the onset and rate of aging of cells, tissues, and organs
- arises because individuals become increasingly different from one another as a functionalists of chronological age
- reflects the diff
a valid biomarker of aging must
monitor a basic aging process
must not monitor the effects of disease
what purposes could be served by an accurate biomarker of aging?
1. delay the onset aging
2. slow the progression of aging
why does the panel of physiological variables reported by Nakamura et al not qualify as a biomarker for aging as defined Mather et al
the panels have not been shown to estimate the rate of biological aging
the experimental observations by Alexis Carrell in the early 20th cen that cultured cells could replicate indefinitely had implications with regard to aging. what are the implications?
cultured cells do not age
the ends of linear chromosomes cannot be replicated during DNA replication. to what does this refer?
the end replication problem
the key result of he experiments conducted by Hayflick was interpreted to mean that cultured cells may not be immortal which led to a point of view in the scientific community that aging may be caused by intracellular processes. what was the key result?
there is a limit to the number of times that a normal human cell may divide before cell division stops
after a fixed number of divisions the cells enter a state of replicative senescence
what typically happens to a normal cell when its telomeres reach what is known as "critical length
the cells become replicatively senescent and then undergo apoptosis
some mammalian somatic cells such as stem cells and cancer cells may circumvent the end-replication problem. has is this accomplished?
these cells express telomerase
list the three roles that are played by telomeres with regard to aging
1. telomeres protect the chromosome end from being incorrectly recognized as DNA damage
2. telomeres protect coding DNA from the "end replication problem"
3. telomeres serve as a gauge for mitotic age
explain why telomere length does not qualify as a biomarker for aging?
telomere length does not qualify as a biomarker for aging because of the five criteria that are required to be fulfilled, telomere length has not been shown to:
- predict the rate of biological aging
- be superior to chronological age
the figure below is taken from an experiment in which an intervention that was designed to slow the rate of aging has been delivered to a group of animals whose transformed age-specific mortality data is represented by the solid line. the transformed age-
the slope of the line of the intervention group must be statistically significantly smaller than that of the control group